1. Field of the Invention
The present invention relates to a method of manufacturing semiconductor devices and more particularly to a method of preliminary processing for the nickel plating which improves the formation of a plated layer of nickel in a semiconductor device and which improves the characteristics of the semiconductor device.
2. Description of the Prior Art
In the production of ohmic contact electrodes for semiconductor devices, e.g., silicon semiconductor devices, the production of electrodes by the process of nickel plating has heretofore been used frequently and particularly the production of electrodes by the process of electroless nickel plating has been resorted to in many cases.
As is well known in the art, the electroless nickel plating is a chemical plating and therefore various considerations have been given to the preliminary processing for the electroless nickel plating and also to the surface treatment in order to increase the adhesion strength of a nickel layer to a semiconductor substrate (silicon substrate) or the adhesion strength of a nickel layer with external lead wires.
In fact, however, even with such considerations the results obtained have not been completely satisfactory.